The present invention relates to an ultrafast continuous imaging apparatus which is capable of continuously picking up a two-dimensionsal image of a high-speed phenomenon such as an explosion and which successively and continuously reproduces the image in a remote place.
A conventional system of continuous imaging comprises the steps of picking up an image with a broadcasting or industrial TV camera, performing A/D conversion on individual frames of output video signals from the TV camera, storing them in a frame memory, and successively transmitting the stored frames to a processing unit. Another conventional system is an image pickup device comprising PN junction photodiodes arranged in an array in the photosensor portion and a switching MOS transistor circuit for successively scanning the photodiode array. When a certain switching MOS transistor is turned on in response to a shift pulse from an X- (or Y-) direction shift register, the signal charges stored in the photodiode connected to that MOS transistor are picked up through a signal line. Also available is an image pickup device that employs a charge-coupled device (CCD) which has a thin oxide film formed on a silicon substrate, with a plurality of electrodes being arranged on the oxide film. When light is incident on the silicon substrate, an amount of charges that is proportional to the intensity of light is stored as an image signal in the potential well under an electrode and the stored charges are scanned to read the image signal.
A problem with the standard TV cameras is that their frame rate is as low as about 30 Hz. Even a high-speed image pickup device in which a two-dimensional solid-state image pickup device is divided into a plurality of segments to be read in parallel to each other achieves only a frame rate of no higher than about 2 kHz. The conventional devices with such low frame rates have been unable to faithfully pick up an image of an explosion or other momentarily changing phenomena. A further problem with these conventional high-speed image pickup devices is that they are incapable of real-time image reception in a remote area and that continuous image cannot be obtained.